For automatic detection of skin print images, in particular finger prints, the skin area to be imaged, in particular the finger tip, is scanned by a sensor. The skin area is positioned on a surface, which is transparent in the case of optical scanning. However, the detection area of the sensor is generally rectangular, the region of interest not usually occupying the entire area detected by the sensor. Image fractions thereby arise which may disturb subsequent evaluation.
It is therefore an object of the present invention to determine the region of interest, such that subsequent image processing steps may be limited to the information contained in the region of interest.